In conventional selective call systems, when a selective call receiver is paged, a message is delivered to the selective call receiver by transmitting the message during a predefined time period identifying the selective call receiver to which the message is intended. The selective call receiver, as is well known, battery saves during the other time period until its predetermined time period occurs, during which, the selective call receiver turns-on and checks if a message is addressed to it. If not, the selective call receiver continue its battery save routine. When a message is addressed to the selective call receiver, the selective call systems have no way of telling if or when the message was received. Therefore, the selective call system can retransmit the same message for a predetermine number of times to ensure that the selective call receiver has every opportunity to receive the message. Unfortunately, the retransmission of messages waste valuable air-time.
Acknowledge-back selective call receivers, however, upon receipt of a message, are able to transmit an acknowledge-back response to the selective call system informing it that the message was received. Therefore, with acknowledge-back selective call receivers, the selective call system does not need to continue retransmitting the same message because the acknowledge back response verifies, among other things, that the message was received. Unfortunately, because the selective call receiver is portable and has a limited energy content battery, the transmission of the acknowledge back responses deplete the battery much quicker. As is well known, transmitting require more energy that receiving, therefore, the selective call receiver may receive pages but is unable to transmit the acknowledge-back responses because the battery is so depleted that it is unable to power-up the transmitter even thought the selective call receiver is still able to receive pages. Under these conditions, the selective call system may choose to continue retransmitting the same message although the message was received.
Therefore, what is needed is a selective call receiver that is able to eliminate or reduce the need for the selective call system to continue retransmitting the same messages when no acknowledge-back response will be transmitted.